Base station with coordinated multiple air-interface operations

ABSTRACT

Base stations with coordinated multiple air-interface operations are provided. In some embodiments, multi-mode base station (BTS) systems operate with different air-interfaces, functionality, or configurations in a coordinated manner. For example, typical applications of such systems can include Macrocell BTS, Picocell BTS, Femtocell BTS, or Access Point (AP), Set Top Box (STB), or Home Gateway, Hot Spot Devices, User Terminal with the capability to perform required base station operations. In some embodiments, various techniques are provided for system improvements and optimizations via radio resource management, including user and system throughput optimization, QoS improvement, interference management, and various other improvements and optimizations. In some embodiments, a system (e.g., a multi-mode device, such as a base station, a repeater, and/or a terminal) includes a multi-mode communication unit, in which the multi-mode communication unit allocates access for communication using at least two modes; and a processor configured to implement at least in part the multi-mode communications unit. In some embodiments, the at least two modes include one or more of the following: frequency band, protocol standard, duplexing format, broadcast mode (e.g., television broadcast and/or a radio broadcast), and one-way communication mode.

CROSS REFERENCE TO OTHER APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/138,453 (Attorney Docket No. AIRHP004+) entitled SYSTEM ANDAPPARATUS OF BASE STATION WITH COORDINATED MULTIPLE AIR-INTERFACEOPERATIONS filed Dec. 17, 2008, which is incorporated herein byreference for all purposes.

BACKGROUND OF THE INVENTION

Conventional cellular base stations (BTSs) normally operate in licensedfrequencies with one air-interface standard. Multiple air-interfaces canbe operated in different carrier frequencies from the same or differentcell sites. User Equipments (UEs) can normally handoff from one BTS toanother BTS, which uses the same or different air-interfaces.

A remote station operates in either licensed frequencies or, if sodesired, in unlicensed frequencies. An example of a remote station is aFemtocell, which typically operates in a licensed frequency band. AFemtocell is a smaller cellular base station or access point thatoperates in either licensed frequencies or, if so desired, in unlicensedfrequencies. It is typically designed for use in residential or businessenvironments. Remote stations use the available broadband access, suchas DSL, cable, T1/E1, or fixed wireless broadband to access thenetworks. Furthermore, many remote stations, such as Femtocells, tunnelthe user and control data through the broadband and connect to thecellular core network backhauls.

The Femtocell incorporates the functionality of a typical base stationwith a simpler, self contained deployment. For example, a typical UMTSFemtocell includes a Node B and RNC with Ethernet for backhaul. Althoughmuch attention is focused on UMTS, the concept is applicable to allstandards, including GSM, EDGE, GPRS, LTE, CDMA, CDMA2000, TD-CDMA andWiMAX solutions. A Femtocell system can also include a router that alsoincludes other Ethernet based items and a Wi-Fi connection.

A Set Top Box (STB) or set top unit (STU) is a device connecting thetelevision to an external source of signal. Furthermore, the STB/STUconverts the signal to be displayed on the television screen. Typically,STBs were used by the cable providers to decode the television signalsthat the cable providers transmitted. More recently, local telephonecompanies have started to provide television service using a STB viatelephone lines or fiber. The Telecommunication Act of 1996 allowednon-cable companies to provide equipment to access the cable network. Anexample of this is the CableCARD. Though the deadline has been movedtwice, as of Jul. 1, 2007, users of cable can now purchase the STB/STUseparately from the cable service. Therefore, innovation in this areawill occur outside the cable providers as well as with the cableproviders.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention are disclosed in the followingdetailed description and the accompanying drawings.

FIG. 1 is a block diagram of a multi-mode BTS in accordance with someembodiments.

FIG. 2 illustrates a cellular base station that operates in bothlicensed and unlicensed bands in accordance with some embodiments.

FIG. 3 illustrates two OFDM based air-interfaces that operate withfrequency band being overlapped in accordance with some embodiments.

FIG. 4 illustrates a multi-mode BTS using the same RF front end and RRMcoordinates the multi-mode transmission with frequency band beingoverlapped in accordance with some embodiments.

FIG. 5 illustrates an OFDM based air-interface and one non-OFDM basedair-interface that operates with frequency band being overlapped inaccordance with some embodiments.

FIG. 6 illustrates soft subcarrier frequency reuse with subcarrier groupand lower level being assigned by the coordinated RRM in accordance withsome embodiments.

FIG. 7 illustrates an OFDM based TDD air-interface operating within FDDDL frequency in accordance with some embodiments.

FIG. 8 illustrates a TDD/FDD multi-mode transmitter and receiver inaccordance with some embodiments.

FIG. 9 illustrates a dual-mode base station that supports cellular andWiFi air-interfaces in accordance with some embodiments.

FIG. 10 illustrates a dual-mode base station that supports cellular andDTV related air-interfaces in accordance with some embodiments.

FIG. 11 illustrates a dual-mode base station that supports cellular andDTV related air-interfaces within the same frequency band in accordancewith some embodiments.

FIG. 12 illustrates an OFDM based DTV air-interface operating withinOFDM based FDD air-interface's DL frequency in accordance with someembodiments.

FIG. 13 illustrates a 2-tier multi-mode BTS system in accordance withsome embodiments.

FIG. 14 illustrates a 2-tier multi-mode BTS system from the RRM point ofview in accordance with some embodiments.

FIG. 15 illustrates a dual-mode device that supports cellular stationand a repeater in accordance with some embodiments.

FIG. 16 illustrates a Femtocell with OFDM based air-interface andMacrocell repeater with OFDM based air-interface operate with frequencyband being overlapped in accordance with some embodiments.

FIG. 17 illustrates a Femtocell with OFDM based air-interface andMacrocell repeater with non-OFDM based air-interface operate withfrequency band being overlapped in accordance with some embodiments.

DETAILED DESCRIPTION

The invention can be implemented in numerous ways, including as aprocess; an apparatus; a system; a composition of matter; a computerprogram product embodied on a computer readable storage medium; and/or aprocessor, such as a processor configured to execute instructions storedon and/or provided by a memory coupled to the processor. In thisspecification, these implementations, or any other form that theinvention may take, may be referred to as techniques. In general, theorder of the steps of disclosed processes may be altered within thescope of the invention. Unless stated otherwise, a component such as aprocessor or a memory described as being configured to perform a taskmay be implemented as a general component that is temporarily configuredto perform the task at a given time or a specific component that ismanufactured to perform the task. As used herein, the term ‘processor’refers to one or more devices, circuits, and/or processing coresconfigured to process data, such as computer program instructions.

A detailed description of one or more embodiments of the invention isprovided below along with accompanying figures that illustrate theprinciples of the invention. The invention is described in connectionwith such embodiments, but the invention is not limited to anyembodiment. The scope of the invention is limited only by the claims andthe invention encompasses numerous alternatives, modifications andequivalents. Numerous specific details are set forth in the followingdescription in order to provide a thorough understanding of theinvention. These details are provided for the purpose of example and theinvention may be practiced according to the claims without some or allof these specific details. For the purpose of clarity, technicalmaterial that is known in the technical fields related to the inventionhas not been described in detail so that the invention is notunnecessarily obscured.

In some embodiments, it is desirable to integrate multiple air-interfaceor functionality into one device so that a single device can provide,for example, multiple services simultaneously or otherwise. Priorapproaches usually focus on integration of the multiple air-interface orfunctionality in a single box or a single chip in order to provideindividual services with lower cost or smaller footprint due tointegration. Some prior approaches address limited communicationsbetween individual air-interfaces, but they are typically on theterminal sides. For example, a possible integration would be putting theFemtocell, LAN router, Wi-Fi, and the DSL/STB in one box. Doing so wouldmake the unit smaller, potentially cheaper and easier to maintain.However, this integration does not improve the utilization of theindividual air-interfaces or the network resources, which is one of themajor areas addressed by the various techniques described herein.

In some embodiments, it is also desirable for multi-tier cellularsystems to operate multiple air-interfaces or the same air-interfaceoperating on the multiple RF frequencies in a coordinated manner inorder to improve the utilization of the individual air-interfaces or thenetwork resources, which is another area addressed by the varioustechniques described herein.

Accordingly, in some embodiments, wireless communications, particularlyrelated to multi-mode devices, such as Macrocell BTS, Picocell BTS,Femtocell BTS, or Access Point (AP), Set Top Box (STB), or Home Gateway,Hot Spot Devices, User terminal with the capability to perform requiredbase station operations, with different air-interface, functionality orconfigurations and being operated in a coordinated manner are describedherein.

Certain embodiments as disclosed herein provide for multi-mode devicesor systems with different air-interface, functionality or configurationsin a coordinated manner. Typical applications of such systems include,for example, Macrocell BTS, Picocell BTS, Femtocell BTS, or Access Point(AP), Set Top Box (STB), or Home Gateway, Hot Spot Devices, Userterminal with the capability to perform required base stationoperations. The devices and systems not only provide the same individualfunctionality as provided by individual mode, but also provide forimprovements and optimizations via radio resource management, including,for example, user and system throughput optimization, QoS improvement,interference management, and various other improvements as describedherein. For example, such improvements and optimizations include thecases in which the multimode is on the same BTS device or on more thantier of BTS devices.

While the various embodiments described herein with respect to BTSsystems, such as access points or Femtocell BTSs, one of ordinary skillin the art will appreciate that, for example, the various embodimentsdescribed herein can include Macrocell BTSs, Picocell BTSs and othertype of wireless stations, such as but not limited to repeaters, relaystations, User Equipments and so on. Also, even though the examples inthe various embodiments described herein are generally described asusing two different modes or two different frequencies or two differentair-interfaces, one of ordinary skill in the art will appreciate thatthe embodiments described herein can be extended to more than two modes,frequencies, and/or air-interfaces.

In some embodiments, the BTS/AP system includes at least part or all ofthe following components:

-   -   1) One or more RF and analog baseband front end (100);    -   2) Digital baseband modem transceiver(s) with PHY and MAC        implemented in hardware or software or both (110);    -   3) Digital processor with or without hardware accelerator        implementing protocol stack software that can include MAC and        layers above it, and supporting the all the required        air-interfaces (120);    -   4) An protocol management unit used to coordinate the protocols        of multiply air-interfaces (130);    -   5) A radio resource management and scheduling unit, which can be        located inside or outside of the management unit, used to        perform resource management and scheduling between the multiply        air-interfaces (140), for example, including but not limited to        the following:        -   Scheduling/load balancing based on QoS, available bandwidth,            interference level;        -   Scheduling/load balancing based on applications, for            example, real-time video vs. file download; and        -   Schedule/load balance based on availability of spectrum over            time or location; and    -   6) Hardware and software interface to backhaul (150).

For example, this approach is illustrated in FIG. 1 in accordance withsome embodiments. In particular, FIG. 1 is a block diagram of amulti-mode BTS in accordance with some embodiments. As will be apparentto one of ordinary skill in the art, the above components arepartitioned based on their functionality not necessarily physicalimplementation entity. As such, they do not have to be separate entitiesin the FIG. 1 implementation.

In some embodiments, the BTS/AP system with the components described inthe previous embodiments supports cellular air-interface(s) on two ormore different frequency bands with at least one being licensed band andat least one in unlicensed band. The operations in the multiplefrequency bands are coordinated based on the embodiments described belowfor the purpose of improving the performance. An example of suchmulti-mode systems is shown in FIG. 2 in accordance with someembodiments.

FIG. 2 illustrates a cellular base station that operates in bothlicensed and unlicensed bands in accordance with some embodiments. Insome embodiments, the same cellular air-interface operates in bothlicensed and unlicensed hands from the same BTS.

In some embodiments, the scheduling algorithm (e.g., implemented using ascheduling function, such as a proportional fairness, round robin, ormaximum throughput (also known maximum C/I) function) in the radioresource management unit can still be derived by optimizing the sum ofthe utility functions of each individual user in each the frequency bandseparately. However, due to the fact that there are single mode UEdevices as well as dual-mode or multi-mode UE devices, a more efficientRRM algorithm as described herein can be used to take advantage of themulti-mode operations and multi-mode UE devices. For example, thisapproach is illustrated in FIG. 2.

In some embodiments, the radio resource management (RRM) algorithm canbe derived by optimizing the sum of the utility functions of eachindividual UE across all the frequency bands in following way(s):

-   1) The RRM reserves a proper portion of the radio resources in each    of the frequency bands, for example, code space in the CDMA case or    resource elements on time-frequency plane in the OFDM case, in order    to schedule the single mode users. The allocated radio resource for    the single mode users can be dynamically adjusted based on the    change of requirements, such as QoS and number of users, and/or    other requirements.-   2) The scheduling algorithm schedules the users in the appropriate    frequency band, which only support single air-interface mode, to the    reserved resources. For example, this can be formulated as an    optimization problem to allocation radio resources in each of the    frequency band for all the single-mode users in that the appropriate    band to individually maximize

${{\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}\; {{U_{i}^{1}( r_{i} )}\mspace{14mu} j}}} = 1},\ldots \mspace{14mu},N$

where r_(i) is the instantaneous data rate of user i, U_(i) ¹(•) is thecorresponding utility function of user i, M_(j) is number of single-modeusers in frequency band j, and N is total number of frequency bands.

-   3) After the single mode users are scheduled, the scheduling    algorithm schedules the users who support multiple frequency bands    to the appropriate frequency band by treating all the bands as one    band (e.g., the same utility function is applied to all the modes of    each user). For example, this can be formulated as an optimization    problem below:

${\max\limits_{x}{\frac{1}{K}{\sum\limits_{j = 1}^{K}( {\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}\; {U_{i}^{2}( {r_{ij}x_{ij}} )}}} )}}},$

-   -   subject to

${{\sum\limits_{j = 1}^{K}( {\sum\limits_{i = 1}^{M_{j}}x_{ij}} )} = 1},{x_{ij} \in \{ {0,1} \}}$

-   -   where r_(ij) is the instantaneous data rate of user i in        frequency band j, U_(i) ²(•) is the corresponding utility        function of user i in any frequency band, M_(j) is number of        multi-mode users in frequency band j, and K is total number of        frequency bands. x_(ij) is defined as

$x_{ij} = \{ \begin{matrix}{1,} & {{if}\mspace{14mu} {radio}\mspace{14mu} {resource}\mspace{14mu} {in}\mspace{14mu} {frequency}\mspace{14mu} j\mspace{14mu} {is}\mspace{14mu} {assigned}\mspace{14mu} {to}\mspace{14mu} {user}\mspace{14mu} i} \\{0,} & {{otherwise}.}\end{matrix} $

-   -   The last condition is to ensure that each multi-mode user will        only be assigned to one frequency (or mode) at any given time.        In the case, that multi-mode UEs can simultaneously support        multiple frequencies, x_(ij) can be dropped.

In some embodiments, the radio resource management procedure of step 3)of the above described embodiment can be done in one of the followingways:

-   a) After the single mode users are scheduled, the scheduling    algorithm schedules the users which support multiple frequency modes    by treating different frequency bands with different priority (e.g.,    different utility functions are used for different frequency band    modes for a multi-mode UE). One example would be to use utility    functions that favors better channel condition(s) on the    non-licensed band mode but use utility functions with proportional    fairness on the licensed band mode. For example, the scheduling can    be resolved as an optimization problem, and the objective is to    allocate radio resources to maximize the sum of the utility    functions of all the users across all the frequency bands, which can    be described as follows:

${\max\limits_{x}{\frac{1}{K}{\sum\limits_{j = 1}^{K}( {\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}\; {U_{ij}^{2}( {r_{ij}x_{ij}} )}}} )}}},$

-   -   subject to

${{\sum\limits_{j = 1}^{K}\; ( {\sum\limits_{i = 1}^{M_{j}}\; x_{ij}} )} = 1},\; {x_{ij} \in \{ {0,1} \}}$

-   -   where r_(ij) is the instantaneous data rate of user i in        frequency band j, U_(ij) ²(•) is the corresponding utility        function of user i in the frequency band j, M_(j) is number of        multi-mode users in frequency band j, and K is total number of        frequency bands. x_(ij) is defined as

$x_{ij} = \{ \begin{matrix}{1,} & {{if}\mspace{14mu} {radio}\mspace{14mu} {resource}\mspace{14mu} {in}\mspace{14mu} {frequency}\mspace{14mu} j\mspace{14mu} {is}\mspace{14mu} {assigned}\mspace{14mu} {to}\mspace{14mu} {user}\mspace{14mu} i} \\{0,} & {{otherwise}.}\end{matrix} $

-   -   The last condition is to ensure that each multi-mode user will        only be assigned to one frequency (e.g., mode) at any given        time. In the case that multi-mode UEs can simultaneously support        multiple frequencies, x_(ij) can be dropped.

-   b) The RRM reserves a proper portion of the radio resources (e.g.,    dedicated resources) in each of the frequency band, for example,    code space in CDMA case or resource elements on time-frequency plane    in OFDM case, in order to schedule the higher priority multi-mode    UEs. After the single mode users are scheduled, the scheduling    algorithm schedules UEs who support multiple frequency band modes    and which has priority level higher than pre-determined threshold to    the dedicated resources. The scheduling is then done to the    remaining UEs. In both dedicated resource scheduling as well as the    remaining resource scheduling, the scheduling can still be treated    an optimization problem and it can either based on step a) in this    embodiment or step 3) in the previous embodiment.

By doing so, it can properly manage QoS requirements by taking advantageof licensed band and non-licensed band operations.

In some embodiments, the BTS/AP system supports more than oneair-interface standards in the same carrier frequency with the samebandwidth or different bandwidth with complete or partial frequencyoverlap, or in different carrier frequencies with the same bandwidth ordifferent bandwidth but with certain overlap in frequency bands.

In some embodiments, two OFDM based air-interfaces operate with carrierfrequency bands being overlapped. For example, a dual-mode LTE and WiMaxBTS/AP system, in which LTE operates at carrier frequency f₁ withbandwidth of B₁ and WiMax operates at carrier frequency f₂ withbandwidth of B₂. B₂ can be equal to, smaller or larger than B₁. Thescheduler and resource management will coordinate the radio resourcesassignment in terms of subcarriers assignment such that overlappedsubcarriers from one of the air-interface will not be assigned any databy the other air-interface or assigned with the power level withacceptable interferences to the first air-interface. For example, thisapproach is illustrated in FIG. 3 in accordance with some embodiments.In particular, FIG. 3 illustrates two OFDM based air-interfaces thatoperate with frequency band being overlapped in accordance with someembodiments.

For example, assuming B₂=5 MHz, B₁=10 MHz, the BTS/AP system can use oneRF front end with bandwidth of 10 MHz for transmitting. In digitalbaseband, the subcarriers in frequency domain belongs t_(o)B₁ thatoverlaps with B₂ will not be assigned any data for LTE air-interface sothat WiMax air-interface will assign data to the B₂=5 MHz band. Itshould be noted that bandwidth assignment can be static, semi-static, ordynamic with real-time assignment down to smallest resource element. Forexample, this approach is illustrated in FIG. 4 in accordance with someembodiments.

FIG. 4 illustrates a multi-mode BTS using the same RF front end and RRMcoordinates the multi-mode transmission with frequency band beingoverlapped in accordance with some embodiments. In some embodiments, theassignment of the subcarriers does not need to be continuous. Forexample, this can also be easily extended to more than two air-interfacecases. As will be apparent to one of ordinary skill in the art, eventhough the example shown LTE and WiMax dual-mode, it can be easilyextended to other modes (e.g., LTE/WiFi, WiMax/WiFi).

In some embodiments, an OFDM based air-interface operates with non-OFDMbased air-interface with frequencies being overlapped. For example, adual-mode LTE and 3G UMTS BTS/AP systems, in which LTE operates atcarrier frequency f₁ with bandwidth of B₁ and 3G UMTS operates atcarrier frequency f₁ with bandwidth of B₂. For example, B₂ can be equalto or smaller than B₁. The scheduler and resource management willcoordinate the radio resources in terms of subcarriers assignment suchthat overlapped subcarriers from the non-OFDM-based air-interface willnot be assigned any data by the other air-interface or assigned with thepower level with acceptable interferences to the first air-interface.For example, assuming B₂=5 MHz, B₁=10 MHz, the subcarriers in B₁ thatoverlaps with B₂ will not be assigned any data for LTE air-interface sothat 3G UMTS air-interface will assign data to the B₂=5 MHz band. Due tothe different characteristics of the RF front end of the twoair-interfaces, two different RF front end will usually used in thiscase, even though one unified RF front end is possible in some cases.For example, bandwidth assignment can be static, semi-static, or dynamicwith real-time assignment down to smallest resource element. Forexample, this approach is illustrated in FIG. 5 in accordance with someembodiments.

FIG. 5 illustrates an OFDM based air-interface and one non-OFDM basedair-interface that operates with frequency band being overlapped inaccordance with some embodiments.

As will be apparent to one of ordinary skill in the art, even though theexample shown LTE and 3G UMTS dual-mode, it can be easily extended toother modes (e.g., WiFi/3G, WiMax/3G, or LTE/GSM, etc.).

In some embodiments, bandwidth usage between the multi-modeair-interfaces can be time-multiplexed, and/or spatial-multiplexed,and/or soft reuse. In some embodiments, soft frequency reuse means thatthe transmit power level from more than one the air-interfaces in theoverlapped frequency are non-zero.

One such example is illustrated in FIG. 6, in which the subcarriergroups and associated power level of the subcarriers are assigned by thecoordinated RRM between different modes. In particular, FIG. 6illustrates soft subcarrier frequency reuse with subcarrier group andlower level being assigned by the coordinated RRM in accordance withsome embodiments. As would be apparent to one of ordinary skill in theart, it should be noted that this embodiment should apply not only tothe case presented in the example, but also apply to the embodimentsabove and below in which more than one air-interfaces operate in thepartially or entire overlapped spectrum frequencies. For example, thisapproach is illustrated in FIG. 6.

For example, the radio resource management can use similar algorithm(s)as in single air-interface in multiple frequency bands case, describedherein. For example, a more efficient RRM algorithm can be derived totake advantage of the multiple air-interface operations and multi-modeUE devices.

In some embodiments, the radio resource management algorithm can bederived by optimizing the sum of the utility functions of eachindividual UE across all the frequency bands in the following way:

-   1) The RRM reserves a proper portion of the radio resources in each    of the frequency bands, for example, code space in the CDMA case or    resource elements on time-frequency plane in the OFDM case, in order    to schedule the single mode users. For example, the allocated radio    resource for the single mode users can be dynamically adjusted based    on the change of requirements such as QoS and number of users and/or    other requirements. Depending on the number of users and the    bandwidth required in each air-interface mode, the resource    management can dynamically increase or decrease the dedicated    resources allocated for single mode UEs.-   2) The scheduling algorithm schedules the users, which only support    single air-interface mode, to the reserved resources in the    appropriate frequency band. For example, this can be formulated as    an optimization problem to allocation radio resources in each of the    frequency bands for all the single-mode users in that band to    individually maximize

${{\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}\; {{U_{i}^{1}( r_{i} )}\mspace{14mu} j}}} = 1},\ldots \mspace{14mu},N$

-   -   where r_(i) is the instantaneous data rate of user i, U_(i) ¹(•)        is the corresponding utility function of user i, M_(j) is number        of single-mode users in frequency band j, and N is total number        of frequency bands.

-   3) After the single mode users are scheduled, the scheduling    algorithm schedules the users that support multiple air-interfaces    to the appropriate frequency band by using the same utility function    to all the air-interfaces a UE can support. For example, this can be    formulated as an optimization problem as

${\max\limits_{x}{\frac{1}{K}{\sum\limits_{j = 1}^{K}\; ( {\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}\; {U_{i}^{2}( {r_{ij}x_{ij}} )}}} )}}},$

-   -   subject to

${{{\sum\limits_{j = 1}^{K}\; ( {\sum\limits_{i = 1}^{M_{j}}\; x_{ij}} )} = 1},\; {x_{ij} \in \{ {0,1} \}}}\mspace{11mu}$

-   -   where r_(ij) is the instantaneous data rate of user i with the        air-interface supported in frequency band j, U_(i) ²(•) is the        corresponding utility function of user i regardless the        air-interface that is being scheduled to use by user i, M_(j) is        number of multi-mode users using the air-interface supported in        frequency band j, and K is total number of air-interfaces        multi-mode BTS supports. x_(ij) is defined as

$x_{ij} = \{ \begin{matrix}{1,} & \begin{matrix}{{if}\mspace{14mu} {radio}\mspace{14mu} {resource}\mspace{14mu} {in}\mspace{14mu} {frequency}\mspace{14mu} j\mspace{11mu} ( {{with}\mspace{14mu} {associated}}\; } \\{ \mspace{14mu} {{air}\text{-}{interface}} )\mspace{14mu} {is}\mspace{14mu} {assigned}\mspace{14mu} {to}\mspace{14mu} {user}\mspace{14mu} i}\end{matrix} \\{0,} & {{otherwise}.}\end{matrix} $

-   -   The last condition ensures that each multi-mode UE will only be        assigned to one air-interface (mode) at any given time. In the        case that multi-mode UEs can simultaneously support multiple        air-interfaces, x_(ij) can be dropped.        In some embodiments, the radio resource management procedure in        step 3) of the above embodiment can be performed in one of the        following ways:

-   a) After the single mode users are scheduled, the scheduling    algorithm schedules the users that support multiple air-interfaces    to the appropriate air-interface by using different utility    functions. For example, the scheduling can be resolved as an    optimization problem, and the objective is to allocate radio    resources to maximize the sum of the utility functions of all the    users across all the appropriate air-interfaces, which can be    described as follows:

${\max\limits_{x}{\frac{1}{K}{\sum\limits_{j = 1}^{K}\; ( {\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}\; {U_{ij}^{2}( {r_{ij}x_{ij}} )}}} )}}},$

-   -   subject to

${{{\sum\limits_{j = 1}^{K}\; ( {\sum\limits_{i = 1}^{M_{j}}\; x_{ij}} )} = 1},\; {x_{ij} \in \{ {0,1} \}}}\;$

-   -   where r_(ij) is the instantaneous data rate of user i with the        air-interface supported in frequency band j, U_(ij) ²(•) is the        corresponding utility function of user i with the air-interface        supported in frequency band j, M_(j) is number of multi-mode        users using the air-interface supported in frequency band j, and        K is total number of air-interfaces multi-mode BTS supports.        x_(ij) is defined as in step 3).

-   b) The RRM reserves a proper portion of the radio resources (e.g.,    dedicated resources) in each of the air-interface, for example, code    space in CDMA case or resource elements on time-frequency plane in    OFDM case, in order to schedule the higher priority multi-mode UEs.    After the single mode users are scheduled, the scheduling algorithm    schedules UEs that support multiple air-interfaces and that have a    priority level higher than pre-determined threshold to the dedicated    resources. The scheduling is then performed on the remaining UEs. In    both dedicated resource scheduling as well as the remaining resource    scheduling, For example, the scheduling can be resolved as an    optimization problem and it can either based on step a) in this    embodiment or step 3) in the previous embodiment, in accordance with    some embodiments.

In some embodiments, the BTS/AP system supports one air-interfacestandard in one carrier frequency operating in FDD (Frequency-DivisionDuplex) mode, and another air-interface standard operating in TDD(Time-Division Duplex), which is in the same carrier frequency as theDownlink (DL) or Uplink (UL) of the FDD mode air-interface standard. TDDoperating within FDD DL frequency case is illustrated in FIG. 7 inaccordance with some embodiments, and TDD operating within FDD ULfrequency is similar in concept. In particular, FIG. 7 illustrates anOFDM based TDD air-interface operating within FDD DL frequency inaccordance with some embodiments.

One special case is that two OFDM based air-interface operate in anoverlapped bandwidth. For example, a dual-mode LTE FDD and LTE TDD,where LTE FDD operates at carrier frequency f₁ with bandwidth of B₁ onDL, f₂ with bandwidth of B₁ on UL, and LTE TDD operates at carrierfrequency f₁ with bandwidth of B₂. B₂ can be equal to, or smaller thanB₁. The scheduler and resource management will coordinate the radioresources in terms of subcarriers assignment such that overlappedsubcarriers from one of the air-interface will not be assigned any databy the other air-interface or assigned with the lower level withacceptable interferences to the first air-interface. For example,assuming B₂=5 MHz, B₁=10 MHz, the subcarriers in B₁ at carrier frequencyf₁ for LTE FDD DL that overlaps with B₂ will not be assigned any datafor LTE FDD so that LTE TDD will assign data to the B₂=5 MHz band atcarrier frequency f₁. For example, the bandwidth assignment can bestatic, semi-static, or dynamic with real-time assignment down tosmallest resource element. This approach is illustrated FIG. 7(described above) in accordance with some embodiments.

An example of one implementation of such dual-mode system is illustratedin FIG. 8 in accordance with some embodiments. In particular, FIG. 8illustrates a TDD/FDD multi-mode transmitter and receiver in accordancewith some embodiments. In this example, it should also be appreciatedthat other TDD operations can be performed simultaneously at f₂ (e.g.,UL of the LTE FDD). It should also be appreciated that, even though twoair-interfaces are given as example, there could be more than twoair-interface supported simultaneously. Those of ordinary skill in theart will further appreciate that even though the described example isLTE FDD and LTE TDD dual-mode, it can be easily extended to other modes(e.g., LTE TDD/WiFi, WiMax TDD/WiFi, WiMax FDD/TDD, UMTS TDD/LTE FDD,LTE, CDMA, OFDM, GSM, WiMax, LTE-A, HDSPA, HSUPA, HSPA, HSPA+, CDMA2000,EDGE, TDMA, 1×EVDO, iDEN, TD-CDMA, and/or other modes or combinations ofmodes).

In some embodiments, the radio resource management algorithm can bederived by optimizing the sum of the utility functions of eachindividual UE across all the frequency bands in the following way:

-   1) The RRM reserves a proper portion of the radio resources in each    of the frequency band, for example, resource elements on    time-frequency plane in OFDM case, in order to schedule the single    mode users. The allocated radio resource for single mode users can    be dynamically adjusted based on the change of requirements such as    QoS and number of users and/or other requirements. Depending on the    number of users and required bandwidth required in each    air-interface mode, the resource management can dynamically increase    or decrease the actual bandwidth allocated to TDD air-interface by    assigning or not assigning the data in some overlapped carriers    while assigning or not assigning them in the FDD air-interface.-   2) The scheduling algorithm schedules the users, which only support    single air-interface mode, to the reserved resources in the    appropriate frequency band. For example, this can be formulated as    an optimization problem to allocation of radio resources in each of    the frequency bands for all the single-mode users in that band to    maximize

${{\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}{{U_{i}^{1}( r_{i} )}\mspace{14mu} j}}} = 1},\ldots \mspace{14mu},N$

-   -   where r_(i) is the instantaneous data rate of user i, U_(i) ¹(•)        is the corresponding utility function of user i, M_(j) is number        of single-mode users in frequency band j, and N is total number        of frequency bands.

-   3) After the single mode users are scheduled, the scheduling    algorithm schedules the UEs that support multiple air-interfaces to    the appropriate frequency band by using the same utility function to    all the air-interfaces a UE can support. For example, this can be    formulated as an optimization problem as

${\max\limits_{x}{\frac{1}{K}{\sum\limits_{j = 1}^{K}( {\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}{U_{i}^{2}( {r_{ij}x_{ij}} )}}} )}}},$

-   -   subject to

${{\sum\limits_{j = 1}^{K}( {\sum\limits_{i = 1}^{M_{j}}x_{ij}} )} = 1},{x_{ij} \in \{ {0,1} \}}$

-   -   where r_(ij) is the instantaneous data rate of user i with the        air-interface supported in frequency band j, U_(i) ²(•) is the        corresponding utility function of user i with the air-interface        that is being scheduled to use by user i, M_(j) is number of        multi-mode users using the air-interface supported in frequency        band j, and K is total number of air-interfaces multi-mode BTS        supports. x_(ij) is defined as

$x_{ij} = \{ \begin{matrix}{1,} & \begin{matrix}{{if}\mspace{14mu} {radio}\mspace{14mu} {resource}\mspace{14mu} {in}\mspace{14mu} {frequency}\mspace{14mu} j} \\( {{with}\mspace{14mu} {associated}\mspace{14mu} {air}\text{-}{interface}} ) \\{{is}\mspace{14mu} {assigned}\mspace{14mu} {to}\mspace{14mu} {user}\mspace{14mu} i}\end{matrix} \\{0,} & {otherwise}\end{matrix} $

-   -   The last condition ensures that each multi-mode UE will only be        assigned to one air-interface (mode) at any given time. In the        case that multi-mode UEs can simultaneously support multiple        air-interfaces, x_(ij) can be dropped. For example, this        approach is illustrated in FIG. 6.

In some embodiments, the radio resource management procedure in step 3)of the above embodiment can be performed in one of the following ways:

-   a) After the single mode users are scheduled, the scheduling    algorithm schedules the users who support multiple air-interfaces to    the appropriate air-interface by using different utility functions.    For example, the scheduling can be resolved as an optimization    problem, and the objective is to allocate radio resources to    maximize the sum of the utility functions of all the users across    all the appropriate air-interfaces, which can be described as    follows:

${\max\limits_{x}{\frac{1}{K}{\sum\limits_{j = 1}^{K}( {\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}{U_{i}^{2}( {r_{ij}x_{ij}} )}}} )}}},$

-   -   subject to

${{\sum\limits_{j = 1}^{K}( {\sum\limits_{i = 1}^{M_{j}}x_{ij}} )} = 1},{x_{ij} \in \{ {0,1} \}}$

-   -   where r_(ij) is the instantaneous data rate of user i with the        air-interface supported in frequency band j, U_(ij) ²(•) is the        corresponding utility function of user i with the air-interface        supported in frequency band j, M_(j) is number of multi-mode        users using the air-interface supported in frequency band j, and        K is total number of air-interfaces multi-mode BTS supports.        x_(ij) is defined as described above in step 3).

-   b) The RRM reserves a proper portion of the radio resources (e.g.,    dedicated resources) in each of the air-interfaces, for example,    resource elements on time-frequency plane in the OFDM case, in order    to schedule the higher priority multi-mode UEs. After the single    mode users are scheduled, the scheduling algorithm schedules UEs    that support multiple air-interfaces and that have a priority level    higher than pre-determined threshold to the dedicated resources. The    scheduling is then done to the remaining UEs. In both dedicated    resource scheduling as well as the remaining resource scheduling,    For example, the scheduling can be resolved as an optimization    problem, and, for example, it can either be based on step a) in this    embodiment or step 3) in the previously described embodiment.

In some embodiments, the BTS/AP system supports a cellular air-interfacein a licensed band and Wi-Fi (IEEE802.1x) or other non-cellular standardon unlicensed bands in a coordinated manner to be described below, inorder to improve the overall system performance, such as shown in FIG. 9in accordance with some embodiments. In particular, FIG. 9 illustrates adual-mode base station that supports cellular and WiFi air-interfaces inaccordance with some embodiments.

In some embodiments, the radio resource management algorithm can bederived by optimizing the sum of the utility functions of eachindividual UE across all the frequency bands in following way:

-   1) The RRM reserves a proper portion of the radio resources in each    of the frequency band, for example, resource elements on    time-frequency plane in OFDM case in order to schedule the single    mode users. For example, the allocated radio resource for the single    mode users can be dynamically adjusted based on the change of    requirements, such as QoS and number of users and/or other    requirements.-   2) The scheduling algorithm schedules the users that only support    single air-interface mode to the reserved resources in the    appropriate frequency band, that is, assign Wi-Fi single mode user    to the frequency associated with the Wi-Fi air-interface and    cellular single mode to the frequency associated with the cellular    air-interface. For example, this can be formulated as an    optimization problem to allocation of radio resources in each of the    frequency bands for all the single-mode users in that band to    maximize

${{\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}{{U_{i}^{1}( r_{i} )}\mspace{14mu} j}}} = 1},\ldots \mspace{14mu},N$

where r_(i) is the instantaneous data rate of user i, U_(i) ¹(•) is thecorresponding utility function of user i, M_(j) is number of single-modeusers in frequency band j, and N is total number of frequency bands.

-   3) After the single mode users are scheduled, the scheduling    algorithm schedules the UEs that support multiple air-interfaces to    the appropriate frequency band by using the same utility function to    all the air-interfaces a UE can support. For example, this can be    formulated as an optimization problem as

${\max\limits_{x}{\frac{1}{K}{\sum\limits_{j = 1}^{K}( {\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}{U_{i}^{2}( {r_{ij}x_{ij}} )}}} )}}},$

-   -   subject to

${{\sum\limits_{j = 1}^{K}( {\sum\limits_{i = 1}^{M_{j}}x_{ij}} )} = 1},{x_{ij} \in \{ {0,1} \}}$

-   -   where r_(ij) is the instantaneous data rate of user i with the        air-interface supported in frequency band j, U_(i) ²(•) is the        corresponding utility function of user i regardless the        air-interface that is being scheduled to use by user i, M_(j) is        number of multi-mode users using the air-interface supported in        frequency band j, and K is total number of air-interfaces        multi-mode BTS supports. x_(ij) is defined as

$x_{ij} = \{ \begin{matrix}{1,} & \begin{matrix}{{if}\mspace{14mu} {radio}\mspace{14mu} {resource}\mspace{14mu} {in}\mspace{14mu} {frequency}\mspace{14mu} j} \\( {{with}\mspace{14mu} {associated}\mspace{14mu} {air}\text{-}{interface}} ) \\{{is}\mspace{14mu} {assigned}\mspace{14mu} {to}\mspace{14mu} {user}\mspace{14mu} i}\end{matrix} \\{0,} & {otherwise}\end{matrix} $

-   -   The last condition ensures that each multi-mode UE will only be        assigned to one air-interface (mode) at any given time. In the        case that multi-mode UEs can simultaneously support multiple        air-interfaces, x_(ij) can be dropped.

In some embodiments, the radio resource management procedure in step 3)of the above described embodiment can be performed in one of thefollowing ways:

-   a) After the single mode users are scheduled, the scheduling    algorithm schedules the users who support multiple air-interfaces to    the appropriate air-interface by using different utility functions.    For example, the scheduling can be resolved as an optimization    problem, and the objective is to allocate radio resources to    maximize the sum of the utility functions of all the users across    all the appropriate air-interfaces, which can be described as    follows:

${\max\limits_{x}{\frac{1}{K}{\sum\limits_{j = 1}^{K}( {\frac{1}{M_{j}}{\sum\limits_{i = 1}^{M_{j}}{U_{i}^{2}( {r_{ij}x_{ij}} )}}} )}}},$

-   -   subject to

${{\sum\limits_{j = 1}^{K}( {\sum\limits_{i = 1}^{M_{j}}x_{ij}} )} = 1},{x_{ij} \in \{ {0,1} \}}$

-   -   where r_(ij) is the instantaneous data rate of user i with the        air-interface supported in frequency band j, U_(ij) ²(•) is the        corresponding utility function of user i with the air-interface        supported in frequency band j, M_(j) is number of multi-mode        users using the air-interface supported in frequency band j, and        K is total number of air-interfaces multi-mode BTS supports.        x_(ij) is defined as described above in step 3).

-   b) The RRM reserves a proper portion of the radio resources (e.g.,    dedicated resources) in each of the frequency bands, for example,    resource elements on time-frequency plane in the OFDM case in order    to schedule the higher priority multi-mode UEs. After the single    mode users are scheduled, the scheduling algorithm schedules UEs    that support multiple frequency band modes and that have a priority    level higher than a pre-determined threshold to the dedicated    resources. The scheduling is then performed on the remaining UEs. In    both dedicated resource scheduling as well as the remaining resource    scheduling, for example, the scheduling can be resolved as an    optimization problem, and it can either based on step a) as    described in this embodiment or step 3) as described above in the    previous embodiment.

In some embodiments, the BTS/AP system supports cellular or wirelessair-interfaces in cellular a licensed band or unlicensed band, and HDTVor mobile TV, such as DVB-T, DVB-H and so on, on unlicensed, licensed orbroadcast band, in a coordinated manner as described below, in order toimprove the overall system performance, as shown in FIG. 10 inaccordance with some embodiments. In particular, FIG. 10 illustrates adual-mode base station that supports cellular and DTV relatedair-interfaces in accordance with some embodiments.

In some embodiments, the BTS/AP system supports cellular or wirelessair-interface in cellular a licensed frequency band or unlicensed band,and HDTV or mobile TV, such as DVB-T or DVB-H in the same frequencyband, in a coordinated manner as described below. One such example is touse two air-interfaces in white space to deliver both cellular anddigital TV services, as shown in FIG. 11 in accordance with someembodiments. In particular, FIG. 11 illustrates a dual-mode base stationthat supports cellular and DTV related air-interfaces within the samefrequency band in accordance with some embodiments.

For example, one special case is the cellular or wireless air-interfaceand digital TV standard are both OFDM based, and they are usingoverlapped frequency band. For example, an LTE operates at carrierfrequency f₁ with bandwidth of B₁ and DVB-T operates at carrierfrequency f₁ with bandwidth of B₂. B₂ can be equal to, smaller than B₁.The scheduler and resource management will coordinate the radioresources in terms of subcarriers assignment such that overlappedsubcarriers from one of the air-interface will not be assigned any databy the other air-interface or assigned with the power level acceptableto the first air-interface. For example, assuming B₂=5 MHz, B₁=10 MHz,the subcarriers in B₁ that overlaps with B₂ will not be assigned anydata for LTE air-interface so that DVB-T air-interface will assign datato the B₂=5 MHz band. For example, the bandwidth assignment can bestatic, semi-static, or dynamic with real-time assignment down tosmallest resource element. This approach is illustrated in FIG. 12 inaccordance with some embodiments. In particular, FIG. 12 illustrates anOFDM based DTV air-interface operating within OFDM based FDDair-interface's DL frequency in accordance with some embodiments. Thoseof ordinary skill in the art will appreciate that even though theexample is described as an LTE and DVB-T dual-mode, it can be easilyextended to other modes (e.g., LTE/DVB-H, WiMax/DVB-T, WiMax/DVB-H,WiFi/DVB-T/H and/or other modes/combinations of modes).

In some embodiments, the various multi-mode BTS systems described hereindo not have to be in one single BTS device or location, that is, the twoor more modes can be deployed in more than one devices or locations toform a multi-tier base station system. In some embodiments, a multi-modeBTS system includes the above described components even though suchcomponents may or may not be co-located. One such example is a 2-tiercellular system with Macrocell BTS employs one air-interface and one ormore Picocell or Femtocell BTSs employ different air-interfaces.

FIG. 13 illustrates a 2-tier multi-mode BTS system in accordance withsome embodiments. In particular, FIG. 13 illustrates the cell systemlevel view of the case in which the Macrocell operates with LTE FDDair-interface standard, one of the Femtocell BTSs uses LTE TDD, and theother uses WiMax FDD air-interface standard.

FIG. 14 illustrates a 2-tier multi-mode BTS system from the RRM point ofview in accordance with some embodiments. As can be seen from FIG. 14,the radio resource management and scheduling now needs to be donethrough coordination of the centralized RRM and localized RRM. In someembodiments, the protocol management that is used for coordinating theprotocols of multiply air-interfaces may also need to be distributed indifferent BTSs (NodeBs).

For example, one special case is that the two BTSs operating with twodifferent OFDM based air-interfaces use the same bandwidth. For example,an LTE Macrocell and WiMax AP, in which LTE operates at carrierfrequency f₁ with bandwidth of B₁ and WiMax operates at carrierfrequency f₂ with bandwidth of B₂. B₂ can be equal to, smaller or largerthan B₁. The resource management from the two BTSs will coordinate theradio resources in terms of subcarriers assignment such that overlappedsubcarriers from one of the air-interface will not be assigned any databy the other air-interface. For example, assuming B₂=5 MHz, B₁=10 MHz,the Macrocell BTS can use an RF front end with bandwidth of 10 MHz fortransmitting. In digital baseband, the subcarriers in frequency domainbelongs to B₁ that overlaps with B₂ will not be assigned any data forLTE air-interface so that WiMax air-interface of AP that has an RF frontend of B₂=5 MHz band will assign data to these subcarriers. For example,the bandwidth assignment can be static, semi-static, or dynamic withreal-time assignment down to smallest resource element. Those ofordinary skill in the art will appreciate that even though the exampleis described as LTE and WiMax, it can be easily extended to other modes(e.g., LTE/WiFi, WiMax/WiFi, and/or other modes/combinations of modes).

For example, another special case is an OFDM based air-interface thatoperates with another non-OFDM based air-interface using the overlappedfrequency. For example, a Femtocell LTE BTS and a 3G UMTS Macrocell BTS,in which LTE operates at carrier frequency f₁ with bandwidth of B₁ and3G UMTS operates at carrier frequency f₁ with bandwidth of B₂. B₂ can beequal to or smaller than B₁. The resource management from the two BTSswill coordinate the radio resources in terms of subcarriers assignmentsuch that overlapped subcarriers from the non-OFDM-based air-interfacewill not be assigned any data by the OFDM-based air-interface orassigned with a power level acceptable by the non-OFDM-basedair-interface. For example, assuming B₂=5 MHz, B₁=10 MHz, thesubcarriers in B₁ that overlaps with B₂ will not be assigned any datafor LTE air-interface so that 3G UMTS air-interface will assign data tothe B₂=5 MHz band. For example, the bandwidth assignment can be static,semi-static, or dynamic with real-time assignment down to smallestresource element. Those of ordinary skill in the art will appreciatethat even though the example is described as LTE and 3G UMTS, it can beeasily extended to other modes (e.g., WiFi/3G, WiMax/3G, or LTE/GSM,and/or other modes/combinations of modes).

In some embodiments, the scheduler in the radio resource management unitcan still be derived by optimizing the sum of the utility functions ofeach individual user for the above described embodiment in the one ofthe following ways:

-   1) The scheduling algorithm schedules the users in each of the BTSs    independently.-   2) The scheduling algorithm schedules the users in both BTSs    coordinately based on well known techniques that have mathematically    formulated the problem on the assumptions that a system is one BTS    and all the user terminals (UEs) being considered are associated    with the BTS under study. As a result, the cost function as well as    its optimization targets how to maximize a cost function with    respect to some or all users in one BTS subject to the capacity    limit and other constraints such that certain performance measures    are achieved. Hence, the scheduler and resource management    algorithms derived from above assumption and theory are for    scheduling UEs in individual BTS without considering other BTSs,    their corresponding schedulers, and their UEs. Mathematically, the    above optimization problem is to assign radio resources in order to    maximize the following cost function:

$\frac{1}{M}{\sum\limits_{i = 1}^{M}{U_{i}( {r_{i}\lbrack n\rbrack} )}}$

-   -   where r_(i)[n] is the instantaneous dates of user i at time n,        U_(i)(•) is the corresponding utility function of user i.    -   Again, all the users are in the same cell or being served by one        BTS, and the optimization is done with respect to one cell or        BTS. For example, on the implementation side, the scheduler can        reside in the BTS, or NodeB in 3GPP terminal. The scheduler is        responsible for assigning radio resources to the UEs in the cell        based on the available radio resources, user channel quality,        user request, and QoS requirements.

In some embodiments, a Macrocell BTS supports one air-interface standardin one carrier frequency in the FDD mode and a BTS with smallerfootprint (e.g., Picocell BTS or Femtocell BTS) supports anotherair-interface standard operates in the TDD in the same carrier frequencyas DL or UL of the FDD mode air-interface standard.

For example, one special case is that two OFDM based air-interfaces areusing the same or different bandwidth, for example, LTE FDD and LTE TDD,in which Macrocell BTS using LTE FDD operates at carrier frequency f₁with bandwidth of B₁ on DL, at f₂ with bandwidth of B₁ on UL, andPicocell or Femtocell BTS using LTE TDD operates at carrier frequency f₁with bandwidth of B₂. B₂ can be equal to, or smaller than B₁. Thescheduler and resource management will coordinate the radio resources interms of subcarriers assignment such that overlapped subcarriers fromone of the air-interface will not be assigned any data by the otherair-interface or assigned with a power level acceptable to theair-interface operates in these subcarriers. For example, assuming B₂=5MHz, B₁=10 MHz, the subcarriers in B₁ at f₁ for LTE FDD DL that overlapswith B₂ will not be assigned any data for LTE FDD so that LTE TDD willassign data to the B₂=5 MHz band at f₁. For example, the bandwidthassignment can be static, semi-static, or dynamic with real-timeassignment down to smallest resource element. Those of ordinary skill inthe art will also appreciate that other TDD operations can be performedsimultaneously at f₂, e.g. UL of the LTE FDD. Those of ordinary skill inthe art will also appreciate that even though two air-interfaces aredescribed in this example, there could be more than two air-interfacesupported simultaneously.

In some embodiments, a BTS with smaller footprint (e.g., a Picocell BTSor Femtocell) BTS supports one air-interface standard in one carrierfrequency in the mode and a Macrocell BTS supports another air-interfacestandard operates in the TDD mode in the same carrier frequency as theDL or UL of the FDD mode air-interface standard. Those of ordinary skillin the art will also appreciate that while the example is described asLTE FDD and LTE TDD dual-mode, it can be easily extended to other modes(e.g., LTE TDD/WiFi, WiMax TDD/WiFi, WiMax FDD/TDD, UMTS TDD/LTE FDD,and/or other modes/combinations of modes).

In some embodiments, the scheduler in the radio resource management unitcan still be derived by optimizing the sum of the utility functions ofeach individual user for the above described embodiment in the one ofthe following ways:

-   1) The scheduling algorithm schedules the users in each of the BTSs    independently.-   2) The scheduling algorithm schedules the users in both BTSs    coordinately based on well known techniques that have mathematically    formulated the problem on the assumptions that a system is one BTS    and all the user terminals (UEs) being considered are associated    with the BTS under study. As a result, the cost function as well as    its optimization targets how to maximize a cost function with    respect to some or all users in one BTS subject to the capacity    limit and other constraints such that certain performance measures    are achieved. Hence, the scheduler and resource management    algorithms derived from above assumption and theory are for    scheduling UEs in individual BTS without considering other BTSs,    their corresponding schedulers, and their UEs. Mathematically, the    above optimization problem is to assign radio resources in order to    maximize the following cost function:

$\frac{1}{M}{\sum\limits_{i = 1}^{M}{U_{i}( {r_{i}\lbrack n\rbrack} )}}$

-   -   where r_(i)[n] is the instantaneous dates of user i at time n,        U_(i)(•) is the corresponding utility function of user i. Again,        all the users are in the same cell or being served by one BTS,        and the optimization is done with respect to one cell or BTS.        For example, on the implementation side, the scheduler can        reside in the BTS, or NodeB in 3GPP terminal. The scheduler is        responsible for assigning radio resources to the UEs in the cell        based on the available radio resources, user channel quality,        user request, and QoS requirements.

In some embodiments, the Femtocell/AP system supports a cellular orwireless air-interface in a cellular licensed frequency band orunlicensed band, and a cellular repeater for a Macrocell BTS with thesame or different air-interface as the Femtocell/AP in the licensedfrequency band, in a coordinated manner as described below and asillustrated in FIG. 15 in accordance with some embodiments. Inparticular, FIG. 15 illustrates a dual-mode device that supportscellular station and a repeater in accordance with some embodiments.

One example is that the cellular or wireless air-interface and repeaterstandard are both OFDM based, and they are using overlapped bandwidth.For example, a LTE Femtocell operates at carrier frequency f₁ withbandwidth of B₁ and the macro repeater using LTE air-interface operatesat carrier frequency f₁ with bandwidth of B₂. B₂ can be equal to,smaller or larger than B₁. The scheduler and resource management willcoordinate the radio resources in terms of subcarriers assignment suchthat overlapped subcarriers from one of the air-interface will not beassigned any data. For example, assuming B₂=5 MHz, B₁=10 MHz, thesubcarriers in B₁ that overlaps with B₂ will not be assigned any data byLTE Femtocell so that LTE Macrocell will assign data to the B₂=5 MHzband. When there are no users using Macrocell repeater, the LTEFemtocell can choose to use the entire B₁=10 MHz bandwidth. For example,the bandwidth assignment can be static, semi-static, or dynamic withreal-time assignment down to smallest resource element. This approach isillustrated in FIG. 16 in accordance with some embodiments. Inparticular, FIG. 16 illustrates a Femtocell with OFDM basedair-interface and Macrocell repeater with OFDM based air-interfaceoperate with frequency band being overlapped in accordance with someembodiments. Those of ordinary skill in the art will also appreciatethat while the example is described as LTE Femtocell/LTE repeater, itcan be easily extended to other modes (e.g., LTE/WiMax, WiMax/LTE,WiFi/LTE, WiFi/WiMax, LTE FDD/LTE TDD, LTE TDD/LTE FDD, etc., and/orother modes/combinations of modes).

Another example is a Femtocell with an OFDM based air-interface thatoperates with a Macrocell repeater with non-OFDM based air-interfaceusing the overlapped bandwidth. For example, an LTE Femtocell and 3GUMTS repeater, in which LTE operates at carrier frequency f₁ withbandwidth of B₁ and 3G UMTS operates at carrier frequency f₁ withbandwidth of B₂. B₂ can be equal to or smaller than B₁. The schedulerand resource management will coordinate the radio resources in terms ofsubcarriers assignment such that overlapped subcarriers from thenon-OFDM-based air-interface will not be assigned any data by the otherair-interface. For example, assuming B₂=5 MHz, B₁=10 MHz, thesubcarriers in B₁ that overlaps with B₂ will not be assigned any datafor LTE air-interface so that 3G UMTS air-interface will assign data tothe B₂=5 MHz band. When there are no users using the Macrocell repeater,the LTE Femtocell can choose to use the entire B₁=10 MHz bandwidth. Forexample, the bandwidth assignment can be static, semi-static, or dynamicwith real-time assignment down to smallest resource element. Thisexample is illustrated in FIG. 17 in accordance with some embodiments.In particular, FIG. 17 illustrates a Femtocell with OFDM basedair-interface and Macrocell repeater with non-OFDM based air-interfaceoperate with frequency band being overlapped in accordance with someembodiments. Those of ordinary skill in the art will also appreciatethat while the example is described as an LTE Femtocell/3G UMTSrepeater, it can be easily extended to other modes (e.g., WiFi/3G,WiMax/3G, LTE/GSM, and/or other modes/combinations of modes).

Although the foregoing embodiments have been described in some detailfor purposes of clarity of understanding, the invention is not limitedto the details provided. There are many alternative ways of implementingthe invention. The disclosed embodiments are illustrative and notrestrictive.

1. A system, comprising: a multi-mode communication unit, wherein themulti-mode communication unit allocates access for communication usingat least two modes; and a processor configured to implement at least inpart the multi-mode communications unit.
 2. The system recited in claim1, wherein the at least two modes include one or more of the following:frequency band, protocol standard, duplexing format, and one-waycommunication mode.
 3. The system recited in claim 1, wherein the atleast two modes include at least one broadcast mode.
 4. The systemrecited in claim 1, wherein the at least two modes include at least onebroadcast mode, and wherein the at least one broadcast mode includes atelevision broadcast mode or a radio broadcast mode.
 5. The systemrecited in claim 1, wherein the processor implements the multi-modecommunication unit.
 6. The system recited in claim 1, wherein theprocessor is a digital processor, and wherein the digital processorimplements the multi-mode communication unit.
 7. The system recited inclaim 1, wherein the multi-mode communication unit includes a pluralityof executable instructions for allocating access for communication usingat least two modes, and wherein the processor is configured to executethe multi-mode communications unit.
 8. The system recited in claim 1,wherein the communication includes wireless communication.
 9. The systemrecited in claim 1, wherein the communication includes wiredcommunication and wireless communication.
 10. The system recited inclaim 1, wherein the system is a multi-mode device, wherein themulti-mode device is a terminal.
 11. The system recited in claim 1,wherein the system is a multi-mode device, wherein the multi-mode deviceis a terminal, and wherein the terminal is selected from one or more ofthe following: a mobile phone, UE, Datacard, broadcast receiver, andbroadcast transmitter.
 12. The system recited in claim 1, wherein thesystem is a multi-mode device, wherein the multi-mode device is a basestation.
 13. The system recited in claim 1, wherein the system is amulti-mode device, wherein the multi-mode device is a repeater.
 14. Thesystem recited in claim 1, wherein the system is a multi-mode device,wherein the multi-mode device communicates with other multi-mode devicesin a peer-to-peer wireless to communication network.
 15. The systemrecited in claim 1, wherein the system is a multi-mode device, whereinthe multi-mode device is a base station, wherein the base station isselected from one or more of the following: a cellular base station, amicrocell base station, a Macrocell base station, a Picocell basestation, a Femtocell base station, an Access Point (AP), a Set Top Box(STB), a Home Gateway, a Hot Spot Device, a User Terminal, a repeater,nodeB, and WiFi.
 16. The system recited in claim 1, wherein themulti-mode communication unit includes a radio resource manager.
 17. Thesystem recited in claim 1, wherein the multi-mode communication unitincludes a multi-mode radio resource manager (RRM).
 18. The systemrecited in claim 1, wherein the multi-mode communication unit includes aradio resource manager, and wherein the radio resource manager performsat least in part the allocation of access for communication using atleast two modes.
 19. The system recited in claim 1, wherein themulti-mode communication unit includes a radio resource manager and aprotocol management unit, wherein the radio resource manager and theprotocol management unit perform at least in part the allocation ofaccess for communication using at least two modes.
 20. The systemrecited in claim 1, wherein the multi-mode communication unit includes aradio resource manager, a protocol management unit, and a plurality ofmulti-mode protocol stacks, wherein the radio resource manager, theprotocol management unit, and the plurality of multi-mode protocolstacks perform at least in part the allocation of access forcommunication using at least two modes.
 21. The system recited in claim1, further comprising: an RF/analog front end.
 22. The system recited inclaim 1, further comprising: an RF/analog front end, wherein themulti-mode communication is provided at least in part using theRF/analog front end.
 23. The system recited in claim 1, furthercomprising: an antenna.
 24. The system recited in claim 1, furthercomprising: an antenna, wherein the multi-mode communication is providedat least in part using the antenna.
 25. The system recited in claim 1,further comprising: a multi-mode modem, wherein the multi-mode modemprovides at least in part for communication using at least two modes.26. The system recited in claim 1, further comprising: a firstmulti-mode modem, wherein the first multi-mode modem provides at leastin part for communication using at least two modes; and a secondmulti-mode modem, wherein the second modem provides at least in part forcommunication in at least two modes.
 27. The system recited in claim 1,further comprising: a first multi-mode modem, wherein the firstmulti-mode modem communicates using at least a first air interface; anda second multi-mode modem, wherein the second multi-mode modemcommunicates using at least a second air interface.
 28. The systemrecited in claim 1, further comprising: the multi-mode communicationunit allocates access for communication using the at least two modes,wherein the access is allocated between at least two multi-mode airinterfaces based on one or more of the following functions: a timemultiplex function, a spatial multiplex function, a soft reuse function,and a frequency reuse function.
 29. The system recited in claim 1,wherein the multi-mode communication unit allocates access forcommunication using the at least two modes, and wherein the access isdynamically allocated between at least two multi-mode air interfacesbased on one or more of the following functions: a time multiplexfunction, a spatial multiplex function, a soft reuse function, and afrequency reuse function.
 30. The system recited in claim 1, wherein themulti-mode communication unit allocates access for communication usingthe at least two modes, and wherein the access is allocated to betweenat least two multi-mode air interfaces using different power levels forwireless transmission for each of the at least two modes.
 31. The systemrecited in claim 1, wherein the multi-mode communication unit allocatesaccess for communication using the at least two modes based on ascheduling function.
 32. The system recited in claim 1, wherein themulti-mode communication unit dynamically allocates access forcommunication using the at least two modes based on a schedulingfunction.
 33. The system recited in claim 1, wherein the multi-modecommunication unit allocates access for communication using the at leasttwo modes based on a scheduling function, and wherein a first modeincludes a time division based mode, and a second mode includes afrequency division based mode.
 34. The system recited in claim 1,wherein the multi-mode communication unit allocates access forcommunication using the at least two modes based on a schedulingfunction, and wherein a first mode includes a time division based modeand a second mode includes a frequency division based mode, including atleast a TDD mode and an FDD mode.
 35. The system recited in claim 1,wherein the multi-mode communication unit allocates access forcommunication using the at least two modes based on a schedulingfunction, and wherein the scheduling function allocates resources. 36.The system recited in claim 1, wherein the multi-mode communication unitallocates access for communication using the at least two modes based ona scheduling function, and wherein the scheduling function includes oneor more of the following: proportional fairness, round robin, andmaximum throughput.
 37. The system recited in claim 1, wherein themulti-mode communication unit allocates access for communication using asingle mode based on a first scheduling function; and the multi-modecommunication unit allocates access for communication using the at leasttwo modes based on a second scheduling function.
 38. The system recitedin claim 1, wherein the multi-mode communication unit allocates accessfor communication using the at least two modes based on a schedulingfunction to coordinate transmissions using a multi-mode modem.
 39. Thesystem recited in claim 1, wherein the multi-mode communication unitallocates access for communication using the at least two modes based ona scheduling function to coordinate transmissions using a firstmulti-mode modem and a second multi-mode modem.
 40. The system recitedin claim 1, wherein the multi-mode communication unit allocates accessfor communication using the at least two modes based on a schedulingfunction to coordinate transmissions using a multi-mode modem, andwherein the scheduling function determines scheduling between aplurality of air interfaces based on one or more of the following:frequency, bandwidth, interference, quality of service, service type,application type, device type, service provider, number of users, andspectrum availability.
 41. The system recited in claim 1, wherein themulti-mode communication unit allocates access for communication usingthe at least two modes based on a scheduling function to coordinatetransmissions using a multi-mode modem, wherein at least one frequencyband is not allocated, and wherein the scheduling function includesscheduling between a plurality of frequency bands, based on one or moreof the following: bandwidth, interference, quality of service, servicetype, application type, device type, service provider, number of users,and spectrum availability.
 42. The system recited in claim 1, whereinthe multi-mode communication unit allocates access for communicationusing the at least two modes based on a scheduling function tocoordinate transmissions using a multi-mode modem, wherein at least onetime-frequency plane is not allocated, and wherein the schedulingfunction includes scheduling between a plurality of time-frequencyplanes based on one or more of the following: bandwidth, interference,quality of service, service type, application type, device type, serviceprovider, number of users, and spectrum availability.
 43. The systemrecited in claim 1, wherein the multi-mode communication unit allocatesaccess for communication using the at least two modes based on ascheduling function to optimize capacity usage based on one or morecriteria.
 44. The system recited in claim 1, wherein the multi-modecommunication unit allocates access for communication using the at leasttwo modes based on capacity and quality of service.
 45. The systemrecited in claim 1, wherein the multi-mode communication unit allocatesaccess for communication using the at least two modes based on a firstscheduling function for a first frequency band mode and based on asecond scheduling function for a second frequency band mode.
 46. Thesystem recited in claim 1, wherein the multi-mode communication unitallocates access for communication using at least two frequency bands,wherein the at least two frequency bands are overlapping.
 47. The systemrecited in claim 1, wherein the multi-mode communication unit allocatesaccess for communication using at least two frequency bands, wherein theat least two frequency bands are overlapping, and wherein a firstfrequency band can be a subset and/or a superset of a second frequencyband.
 48. The system recited in claim 1, wherein the multi-modecommunication unit allocates access for communication using at least twofrequency bands, wherein the at least two frequency bands areoverlapping, wherein a first frequency band can be a subset and/or asuperset of a second frequency band, and wherein the first frequencyband is OFDM and the second frequency band is non-OFDM.
 49. The systemrecited in claim 1, wherein the multi-mode communication unit allocatesaccess for communication using at least two frequency bands, wherein theat least two frequency bands are overlapping, wherein power levels withacceptable interferences are assigned.
 50. The system recited in claim1, wherein the multi-mode communication unit allocates access forcommunication using at least two frequency bands, wherein the at leasttwo frequency bands are overlapping, wherein access allocation variesover time.
 51. The system recited in claim 1, wherein the multi-modecommunication unit allocates access for communication using at least twofrequency bands, wherein the at least two frequency bands areoverlapping, wherein a first frequency band can be a subset and/or asuperset of a second frequency band, and wherein the first frequencyband is OFDM and the second frequency band is OFDM.
 52. The systemrecited in claim 1, wherein the multi-mode communication unit allocatesto access for communication using at least two frequency bands, whereinthe at least two frequency bands are overlapping, wherein a firstfrequency band can be a subset and/or a superset of a second frequencyband, and wherein the first frequency band is non-OFDM and the secondfrequency band is non-OFDM.
 53. The system recited in claim 1, furthercomprising: a multi-mode modem, wherein the multi-mode modemcommunicates in a first mode using a first protocol in an unlicensedfrequency band and communicates in a second mode using the firstprotocol in a licensed frequency band.
 54. The system recited in claim1, further comprising: a multi-mode modem, wherein the multi-mode modemcommunicates in a first mode using a first protocol in an unlicensedfrequency band and communicates in a second mode using the firstprotocol in a licensed frequency band, and wherein the unlicensedfrequency band is not allocated.
 55. The system recited in claim 1,further comprising: a multi-mode modem, wherein the multi-mode modemcommunicates in a first mode using a first protocol in an unlicensedfrequency band and communicates in a second mode using the firstprotocol in a licensed frequency band, wherein the unlicensed frequencyband is not allocated, and wherein the first protocol includes one ormore of the following: LTE, CDMA, OFDM, GSM, WiMax, LTE-A, HDSPA, HSUPA,HSPA, HSPA+, CDMA2000, EDGE, TDMA, 1×EVDO, iDEN, TD-CDMA.
 56. The systemrecited in claim 1, further comprising: a first multi-mode modem,wherein the first multi-mode modem communicates in a first mode using afirst protocol in an unlicensed frequency band; and a second multi-modemodem, and wherein the second multi-mode modem communicates in a secondmode using the first protocol in a licensed frequency band.
 57. Thesystem recited in claim 1, wherein the system is a 2-tier multi-modebase station system, wherein the multi-mode communication unit operatesusing a first air-interface standard and a second air-interfacestandard.
 58. The system recited in claim 1, wherein the system includesa repeater, and wherein the repeater operates as a terminal and as abase station.
 59. A system, comprising: a processor configured to: amulti-mode communication unit, wherein the multi-mode communication unitallocates access for communication using at least two modes; and amemory coupled to the processor and configured to provide the processorwith instructions.
 60. A system, comprising: a processor configured to:a multi-mode communication unit, wherein the multi-mode communicationunit allocates access for communication using at least two modes; and acommunication interface coupled to the processor and configured toprovide the communication interface with instructions.
 61. A method,comprising: executing a multi-mode communication unit, wherein themulti-mode communication unit allocates access for communication usingat least two modes, and wherein the multi-mode communication unitallocates access for communication using the at least two modes based ona scheduling function to coordinate transmissions using a multi-modemodem; and executing radio resource manager, wherein the radio resourcemanager performs at least in part the allocation of access to themulti-mode modem for communication using at least two modes.
 62. Acomputer program product, the computer program product being embodied ina computer readable storage medium and comprising computer instructionsfor: to executing a multi-mode communication function, wherein themulti-mode communication function allocates access for communicationusing the at least two modes; executing radio resource manager, whereinthe radio resource manager performs at least in part the allocation ofaccess for communication using at least two modes; and a protocolmanagement unit, wherein the protocol management unit perform at leastin part the allocation of access for communication using at least twomodes.